A data center can be modeled as rows of racks that house electronic systems, such as computing systems. The computing systems (such as computers, storage devices, networking devices, etc.) consume significant amounts of power for their operation. In addition, these computing systems disperse large amounts of heat during their operation. The computing systems can also affect the humidity, airflow, and other environmental conditions in the data center. In order to ensure proper operation of these systems, the computing systems need to be maintained within tight operating ranges of environmental conditions (e.g., temperature). The computing systems may also need to be maintained within a desired humidity range, a desired air pressure range, and without the presence of moisture or fire. The failure to maintain such environmental conditions results in system failures.
Conventional data centers employ different forms of environmental control devices or cooling mechanisms to keep the computing systems within a safe temperature range. For example, in most data centers, cooling units, such as computer room air conditioning (A/C) or air handling units distribute cold air or cold liquid (such as water and air) to different racks via aisles between the racks. The computing systems of the data center reside in these racks.
There is a significant energy cost associated with maintaining safe environmental conditions in a data center. Cold air and sometimes liquid coolant must be moved through the aisles, racks, and computing systems. In order to optimize this energy usage for controlling environmental conditions, the environmental control devices in the data center must precisely control the volume and temperature of the cooling air or liquid that must be pushed through the sub-plenum and racks of the data center. Unfortunately, many data centers operate by pushing too much cooling air or liquid at very low temperature, thereby incurring significant and unnecessary energy costs. Other data centers must cool an entire room to meet the environmental requirements for a single computing device, thereby wasting energy relative to the other computing devices in the data center.
U.S. Pat. No. 7,031,870 describes a method for evaluating one or more components in a data center, in which inlet and outlet temperatures of one or more heat dissipating devices are detected. In addition, the temperatures of air supplied by one or more computer room air conditioning (CRAC) units are also detected. Indices of air re-circulation for the one or more heat dissipating devices are calculated based upon the detected inlet temperatures, outlet temperatures and supplied air temperatures. The indices of air re-circulation are determined at various flow field settings of air delivered to the one or more heat dissipating devices and the one or more components are evaluated based upon changes in the indices of air re-circulation for the one or more heat dissipating devices at the various flow field settings.